Self-Assembled Complex Three-Phase Core-Shell Nanostructure of Au-CoFe2-TiN with a Magneto-Optical Coupling Effect

Nanostructured plasmonic-magnetic metamaterialshave gainedgreat research interest due to their enhanced magneto-optical couplingeffects. Here, we report a complex three-phase nanocomposite designcombining ferromagnetic CoFe2 with plasmonic TiN and Auas a multifunctional hybrid metamaterial using either a cogrowth ora templated method. Via the first method of cogrowing three phases,three different morphologies of Au-CoFe2 core-shellnanopillars were formed in the TiN matrix. Via the second method ofsequential deposition of a TiN-Au seed layer and a TiN-CoFe2 layer, highly ordered and uniform single-type core-shellnanopillars (i.e., the CoFe2 shell with a Au core) formin the TiN matrix. Both cogrowth and templated growth TiN-CoFe2-Au hybrid systems exhibit excellent epitaxial quality,hyperbolic dispersion, magnetic anisotropy, and a magneto-opticalcoupling effect. This study provides an effective approach for achievinghighly uniform multiphase vertically aligned nanocomposite structureswith well-integrated optical, magnetic, and coupling properties.